XML 107 R90.htm IDEA: XBRL DOCUMENT
v3.19.1

Accumulated Other Comprehensive Income (Components of Accumulated Other Comprehensive Income) (Details) - CAD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2018 | Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |
Beginning Balance | $ (165) | $ 135
Other comprehensive income (loss) before reclassifications | 504 | (347)
Reclassification from AOCI, Current Period, before Tax, Attributable to Parent | (1) | 47
Net current period other comprehensive income (loss) | 503 | (300)
Ending Balance | 338 | (165)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |
Beginning Balance | (3) | (21)
Other comprehensive income (loss) before reclassifications | 2 | 10
Reclassification from AOCI, Current Period, before Tax, Attributable to Parent | (6) | 8
Net current period other comprehensive income (loss) | (4) | 18
Ending Balance | (7) | (3)
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |
Beginning Balance | (243) | (283)
Other comprehensive income (loss) before reclassifications | 0 | 0
Reclassification from AOCI, Current Period, before Tax, Attributable to Parent | 9 | 40
Net current period other comprehensive income (loss) | 9 | 40
Ending Balance | (234) | (243)
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member] |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |
Beginning Balance | 48 | (49)
Other comprehensive income (loss) before reclassifications | (122) | 97
Reclassification from AOCI, Current Period, before Tax, Attributable to Parent | 0 | 0
Net current period other comprehensive income (loss) | (122) | 97
Ending Balance | (74) | 48
Accumulated Net Available For Sale Securities Gain (Loss) [Member] |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |
Beginning Balance | 3 | (1)
Other comprehensive income (loss) before reclassifications | 0 | 5
Reclassification from AOCI, Current Period, before Tax, Attributable to Parent | (4) | (1)
Net current period other comprehensive income (loss) | (4) | 4
Ending Balance | (1) | 3
Accumulated Foreign Currency Adjustment Attributable to Parent [Member] |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |
Beginning Balance | 30 | 489
Other comprehensive income (loss) before reclassifications | 624 | (459)
Reclassification from AOCI, Current Period, before Tax, Attributable to Parent | 0 | 0
Net current period other comprehensive income (loss) | 624 | (459)
Ending Balance | $ 654 | $ 30

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount before tax of increase (decrease) in accumulated equity from transactions and other events and circumstances from non-owner sources, attributable to parent. Excludes net income (loss), and accumulated changes in equity from transactions resulting from investments by owners (distributions to owners). + References No definition available. + Details
Name: | us-gaap_AociBeforeTaxAttributableToParent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount after tax, before reclassification adjustments, of other comprehensive income (loss), attributable to parent. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 55 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=84158357&loc=d3e1436-108581 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14A -URI http://asc.fasb.org/extlink&oid=84228862&loc=SL7669686-108580 + Details
Name: | us-gaap_OciBeforeReclassificationsNetOfTaxAttributableToParent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of tax expense (benefit) allocated to other comprehensive income (loss) attributable to parent entity. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 50 -Paragraph 1A -Subparagraph (c)(3) -URI http://asc.fasb.org/extlink&oid=84161450&loc=SL4573702-111684 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 45 -Paragraph 19 -URI http://asc.fasb.org/extlink&oid=96868048&loc=SL4569616-111683 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 45 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=96868048&loc=SL4569643-111683 + Details
Name: | us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount before tax of reclassification adjustments of other comprehensive income (loss) attributable to parent. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14A -URI http://asc.fasb.org/extlink&oid=84228862&loc=SL7669686-108580 + Details
Name: | us-gaap_ReclassificationFromAociCurrentPeriodBeforeTaxAttributableToParent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=ema_AccumulatedNetAvailableForSaleSecuritiesGainLossMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=us-gaap_AccumulatedTranslationAdjustmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |